c-ubsan.c (ubsan_instrument_shift): Perform the MINUS_EXPR in unsigned type.

	* c-ubsan.c (ubsan_instrument_shift): Perform the MINUS_EXPR
	in unsigned type.

	* c-c++-common/ubsan/undefined-2.c: New test.

From-SVN: r216593

4 files changed, 37 insertions, 5 deletions

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index f95866c..05254c8 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2014-10-23  Marek Polacek  <polacek@redhat.com>
+
+	* c-ubsan.c (ubsan_instrument_shift): Perform the MINUS_EXPR
+	in unsigned type.
+
 2014-10-22  Jakub Jelinek  <jakub@redhat.com>
 	    Yury Gribov  <y.gribov@samsung.com>
 
diff --git a/gcc/c-family/c-ubsan.c b/gcc/c-family/c-ubsan.c
index 5a42303..7f4dc25 100644
--- a/gcc/c-family/c-ubsan.c
+++ b/gcc/c-family/c-ubsan.c
@@ -128,19 +128,19 @@ ubsan_instrument_shift (location_t loc, enum tree_code code,
   tree op1_utype = unsigned_type_for (type1);
   HOST_WIDE_INT op0_prec = TYPE_PRECISION (type0);
   tree uprecm1 = build_int_cst (op1_utype, op0_prec - 1);
-  tree precm1 = build_int_cst (type1, op0_prec - 1);
 
   t = fold_convert_loc (loc, op1_utype, op1);
   t = fold_build2 (GT_EXPR, boolean_type_node, t, uprecm1);
 
   /* For signed x << y, in C99/C11, the following:
-     (unsigned) x >> (precm1 - y)
+     (unsigned) x >> (uprecm1 - y)
      if non-zero, is undefined.  */
   if (code == LSHIFT_EXPR
       && !TYPE_UNSIGNED (type0)
       && flag_isoc99)
     {
-      tree x = fold_build2 (MINUS_EXPR, integer_type_node, precm1, op1);
+      tree x = fold_build2 (MINUS_EXPR, unsigned_type_node, uprecm1,
+			    fold_convert (op1_utype, op1));
       tt = fold_convert_loc (loc, unsigned_type_for (type0), op0);
       tt = fold_build2 (RSHIFT_EXPR, TREE_TYPE (tt), tt, x);
       tt = fold_build2 (NE_EXPR, boolean_type_node, tt,
@@ -148,13 +148,14 @@ ubsan_instrument_shift (location_t loc, enum tree_code code,
     }
 
   /* For signed x << y, in C++11 and later, the following:
-     x < 0 || ((unsigned) x >> (precm1 - y))
+     x < 0 || ((unsigned) x >> (uprecm1 - y))
      if > 1, is undefined.  */
   if (code == LSHIFT_EXPR
       && !TYPE_UNSIGNED (TREE_TYPE (op0))
       && (cxx_dialect >= cxx11))
     {
-      tree x = fold_build2 (MINUS_EXPR, integer_type_node, precm1, op1);
+      tree x = fold_build2 (MINUS_EXPR, unsigned_type_node, uprecm1,
+			    fold_convert (op1_utype, op1));
       tt = fold_convert_loc (loc, unsigned_type_for (type0), op0);
       tt = fold_build2 (RSHIFT_EXPR, TREE_TYPE (tt), tt, x);
       tt = fold_build2 (GT_EXPR, boolean_type_node, tt,
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a3f1308..701fadb 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2014-10-23  Marek Polacek  <polacek@redhat.com>
+
+	* c-c++-common/ubsan/undefined-2.c: New test.
+
 2014-10-10  Kirill Yukhin  <kirill.yukhin@intel.com>
 
 	* gcc.target/i386/pr63600.c: New.
diff --git a/gcc/testsuite/c-c++-common/ubsan/undefined-2.c b/gcc/testsuite/c-c++-common/ubsan/undefined-2.c
new file mode 100644
index 0000000..05dea44
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/ubsan/undefined-2.c
@@ -0,0 +1,22 @@
+/* { dg-do run } */
+/* { dg-options "-fsanitize=undefined -fno-sanitize-recover=signed-integer-overflow" } */
+/* { dg-additional-options "-std=gnu11" { target c } } */
+/* { dg-additional-options "-std=c++11" { target c++ } } */
+
+volatile int w, z;
+
+__attribute__ ((noinline, noclone)) int
+foo (int x, int y)
+{
+  z++;
+  return x << y;
+}
+
+int
+main ()
+{
+  w = foo (0, -__INT_MAX__);
+  return 0;
+}
+
+/* { dg-output "shift exponent -\[^\n\r]* is negative\[^\n\r]*(\n|\r\n|\r)" } */